This invention relates to a novel melt processible, multi-phase thermoplastic composition of a crystalline polyolefin resin, a crosslinked ethylene-containing copolymer having units derived from glycidyl methacrylate or glycidyl acrylate and a method for making such thermoplastic compositions.
Blends of plastics and elastomers are generally not compatible with each other and the resulting compositions have unsatisfactory physical properties. Blends of nonpolar plastics and polar elastomers normally require the incorporation therein of a compatibilizing agent in order to obtain satisfactory physical properties. The addition of a compatibilizing agent adds to the expense of the blend and makes the process for making such blends more complicated. Frequently, the elastomer component of such a blend is uncured which results in a composition having high compression set and high oil swell. However, it is advantageous to blend crystalline polymers with certain elastomers in such a manner that they are compatible with each other and result in thermoplastic elastomer compositions that have good elastomeric characteristics and stress-strain properties, e.g., high tensile and tear strength, high compression set resistance and permanent set resistance, high percent elongation, adequate low and high temperature properties, and oil resistance.
It is important, especially from an economic standpoint that the thermoplastic compositions are easily processible on thermoplastic equipment with little or no modification. Further, scrap material of the thermoplastic compositions should be capable of being reground and reprocessed with substantially no significant change in the physical properties of the thermoplastic composition.